Hello all,

I have a 2004 cooper S with 32K miles. I am running ngk plugs, MSD ignition, miltek exhaust, mini-maddness 15% pulley, mini-madness cold air intake. There are the specs on the car - here is the issue .

I was driving up my street, hit about 4K rpm and BANG!!!!! - I thought I ran somehting over and it hit my car. I was about 100 yards from the house, so I pulled into the driveway and then the engine sputter started and I just turned it off. Upon opening the hood, I found that a sparkplug was completely blown out of the head (even had a dent in my hood). I checked the threads on the spark plug and they were fine. I checked the threads where it seats, and they were completely flat and gone. It appears that the plug was blown out of the head.

right now, the car is sitting at nielo mini waiting to get looked over. At this point, I am confident that it should be under warranty - given that the modifications would not have resulted in this type of issues (I have been very careful to not make modifications that would void the warranty, even talked to the dealship and techs about what I could do and not do).

Has anyone had this issue before?

Any help would be great - thanks.

 

Yes It happens not very often. Must have had a stripped thread in the head during a plug change. If anti-seize compound was not used and plugs changed while engine hot can mess threads. Mostly I have seen the guts of the plug come out or compression leaks thru the plug itself. The head can be fixed with a heli-coil, dealer should be capable of fix if they do not warranty it.

 

Jagfixer - thanks for the respose. I am fairly confident that there was no striping on the install, as it was done more then 2 years ago (issue would have arose before now). A small dab was used, but the engine was cold on the change (I took several precautions - only the paranoid surive ).

Where can a heli-coil can be picked up? How are they on life and wear? Would I be better off just getting a new head?

Again, thanks for the answers.

 

Try this search on 'helicoil' - lots of threads on it. Pros/cons/experiences.
Definitely not worth getting a new head. They can be purchased at many automotive stores - but if you don't have experience with them you should go to a shop that does. Several reports of the helicoil being installed with the head in place, which saves a bunch of labor $.

 

Not sure on the warranty part as most dealers would look at your mods and deny it on the spot (pulley being the big one). Your dealer may be willing to work with it but I wouldn't go to any other dealer as you could get flagged.

As for the blowing of the plug, there are a ton of threads on this and most are easily repaired with a helicoil (there is another method but I can't remember the name) as mentioned.

Do you know which cylinder one blew? #2?

One theory I have on this matter is that whomever installed the plugs did not make sure they were in all the way before torquing. Typically there is a spring style washer on the plug that gets tight and then loosens a bit before seating. If the installer did not tighten in down all the way it is possible that the plug was never in all the way allowing movement thus stripping and blowing out. However, it is a theory as I have yet to examine one in person.

 

Thanks for the great responses and based on this feedback and direction I have dug a littler deeper. I am thinking that I am going to go with the timesert method (seems to be a little more involved, but appears to be much more stable on the head).

Yeah, cylinder #2 was blown. From what I have been reading, it appears that #2 seems to be the first to go.

Again, thank you all for the feedback.

My car is currently waiting to be "examined" by a technician at neilo mini. I got a call today and we had a wonderful discussion. Here is a quick except of the conversation:
Needless to say, I have never had to much sucess with the folks at niello. The last time my car was in the shop their, it took 4 months to get it back (long story, but they did the work, completely messed it up, had to wait 6 weeks for the parts to do it over).

I will keep you all posted. My gut tells me I will be picking up my car on monday .

 

Ummm

JCW is about 11% not 14... You probably will be picking it up.

 

Now would be the time to have a ported Head installed... the head is going to HAVE to come off to be repaired...Just a thought!!

Just me..........................

Thumper

 

Actually, they can do it without removing the head. (Although I don't think it is a great idea) Many have had it done without the removal of the head.

 

Just be aware of the facts before quoting things. JCW is ~11% reduction. Not sure if they'll start arguing that as a point, but it would give them an irrelevant "edge."

- Matt

 

The other method is to use a KD Backtap. The Mini plugs are 14mm so the BackTap is the 3545 and you can find one with a Google search. A friend of mine came to me with a blown plug and we used the Backtap and it has not come loose again and has been no problem. We did it on a cold head and it was much easier than a helicoil.

My theory is that you not only have to use a torque wrench to install the plugs but that it needs to be done with the motor stone cold. I check my plugs, Denso Iridiums every oil change at 5000 mile intervals. 22 foot pounds and they have not loosened since the install.

Rich

 

BackTap or HeliCoil is good. Need to use lots of grease on Helicoil if drilling. Have used them on outboards ( OMC,Mercury, Suzuki) diesels ( Cummins, Cat), and many aluminum head European cars ( Jags ).

 

Thanks rich and jagfixer for the feedback. I will let you know which method I end up using (helicoil, timesert or KD backtap) - once I get the car back from the dealership .

 

Rich - did you remove the head to use the KD3545 Backtap tool? Or can this be done with the head still on the block?

 

The pulley wont be your problem, its the fact the YOU changed the plugs out and now its YOUR fault because YOU were the last one to touch them.
Thats the way it goes at the dealer. You should have put the OEM back in befor you brought it to the shop......

 

That is dishonest and the pulley will be the issue. They will likely blame it on the increase in pressure within the head. I have never heard of a dealer deny warranty because plugs have been changed.

 

Well, we will see to morrow morning what nielo says. When they deny it (I am just planning on the worst), i will just pick it up and attempt, in this order, the fix:

1. Thread Chaser - this seems like the least intrusive method, so I will attempt it first.
2. If #1 does not work, I will move onto the timesert method. It seems that sleeving the aluminum head with steel inserts is highly recommended anyhow.

Thanks again everyone for your feedback.

 

Not a simple chase as that will drive chips down into the cylinder and if the outside threads are really gone it will be near impossible to set the tap correctly. The BackTap goes in and chases the threads on the way out. It locks in on the good threads so you know it's not cutting new ones and the chips come up not down. We'll worth looking for one. They are made by KD tools so your local auto parts store can probably order it. You need the 14mm one.

No need to remove the head. Do it stone cold not that it will be a problem since it hasn't been run in a while and cover the tap with some grease so the chips stick to it. If it works you'll have it done in under a half hour with most of the time taking the big breath before you start.

Good luck and let us know how you do.



Rich

 

What is dishonest?? I have seen plugs blow out and checked out the remaing just to find that they were all loose.. Now who's fault is that?? The dealership or You for not tightening them properly? Either way hope you get it worked out.

 

Having aftermarket plugs in will mean that you will not be covered under warranty for a problem with the spark plugs.

My MINI service department warns people of this. If they see aftermarket plugs, they mention it to you and ask if you want them to put stock plugs back in (at your cost, I assume). Aftermarket plugs are notorious for this problem.

It has nothing to do with the pulley. The same problem occurs on Coopers, so the pulley has nothing to do with it.

 

Putting OEM back on to try and trick the dealer. That is dishonest... Kinda scares me that you don't even recognize that.

 

OOOh wahhhh give me a break. Sorry everoyone thinks the same sometimes and I'm the one to say it

 

No not everyone.... and you are not the first.

 

Something to keep in mind, the stock plugs are not scheduled for replacement until 100,000 miles. If you are changing them out at every 5,000 miles they're going to hammer you on it saying you put 20 times the wear on the head's spark plug threads and also probably tag you with overtorquing the plugs.

I'm willing to bet (unfortunately) that this will be coming out of your pocket.

 

Lets talk defective head. I take the plugs in and out on a BMW r series motorcycle (aluminum heads) to do valve adjustments. Using a very good torque wrench (snap-on) they go back in at the correct torque. Same thing when I changed plugs on the MINI. On occassions I will just check the torque on the MINI and the R1150RS. No problems. BMW does have defective parts. Right now there are defective valve stems plaguing some of the bikes.

Jody